The disclosure generally relates to a clock data recovery circuit and, more particularly, to a clock data recovery circuit capable of accelerating the loop response speed and does not easily result in frequency drift.
A clock data recovery circuit is widely employed in many applications, but the conventional clock data recovery circuit typically uses the analog loop filter. Therefore, in the situation of that the input terminal of the clock data recovery circuit does not receive any data signal over a certain period of time, it easily causes frequency drift in the resulting sampling clock signal.
The frequency drift problem may be reduced by replacing the analog loop filter with more complex digital loop filter, but it would easily result in insufficient loop response speed, thereby causing the conventional clock data recovery circuit to be unable to support applications having higher data signal frequency.